Do you want to know how to get the perfect top and bottom layers for 3D printing? These settings can add some unique features to your models.
To achieve the perfect top and bottom layers, you must have a good top and bottom thickness between 1.2 and 1.6 mm. Enable Ironing, and Top/Bottom Patterns are beneficial settings. Monotonic Top/Bottom Order offers a smoother extrusion pathway, which is another setting that users find helpful.
These are the fundamental responses, but keep reading for more valuable details on some excellent top & bottom layers.
What Does 3D Printing Top & Bottom Layers / Thickness Mean?
The layers at the top & bottom of your 3D model are simply referred to as the Top and Bottom Layers. They are printed as solid pieces to close your 3D prints’ top and bottom. In Cura, you can change the Top/Bottom Thickness and the Number of Top & Bottom Layers.
The height or thickness of the top and bottom layers, respectively, is known as the top/bottom layer thickness. Because some of these layers make up the print’s skin, they will impact how the 3D print ultimately appears (the outermost surface of the print).
Your models will be more robust if your top and bottom layers are thicker. Because they will be solid rather than printed with an infill pattern and density. These settings have an impact on how watertight your model will be as well. Your models will be more watertight if the top and bottom are thicker.
The main disadvantage is that your model will use more material and take longer to print the thicker the top and bottom are. To better understand the Top/Bottom layers, you can check this video that breaks down the inner structure of a 3D model.,
He also explains different Top/Bottom layer settings and how they relate to the wall and the infill of the print. We’ll take a closer look at these settings in the next section.
Best Top/Bottom Layers for 3D Prints
In Cura, there are numerous Top/Bottom settings that you can modify, including:
- Top/Bottom Thickness
- Top Thickness
- Top Layers
- Bottom Thickness
- Bottom Layers
- Top/Bottom Pattern
- Monotonic Top/Bottom Order
- Enable Ironing
Let’s look at the best Cura settings for each of these Top/Bottom options. It is usually advised to have a top/bottom layer thickness of at least 1–1.2 mm (make sure it is a multiple of your layer height). Print flaws like pillowing and sagging are prevented by doing this.
Top/Bottom Thickness
To properly close up the tops and bottoms of your models, the ideal top/bottom thickness typically ranges from 1.2mm to 1.5mm. The default value of 0.8mm is a minimum rather than the best value for models, and it can easily result in gaps in your model’s tops.
We advise using 1.6mm and higher if you want to achieve a robust top/bottom thickness. It’s a good idea to conduct your own testing using some simple models so you can compare how they all appear in reality.
You can experiment with various 3D prints to see how the 3D models turn out because different models and geometries will affect their appearance.
Top Thickness & Bottom Thickness
When you enter your Top/Bottom Thickness settings, the Top Thickness & Bottom Thickness configurations will automatically update. When you enter 1.6mm for the Top/Bottom Thickness in Cura, the separate settings for Top Thickness and Bottom Thickness will also adjust to that value. The same values typically work well for both settings. But you can change them independently. Still, you can raise the Top Thickness value by about 30–60% if you notice that your top layers aren’t sealing up properly.
Top Layers & Bottom Layers
The Top/Bottom Thickness setting modifies the configuration of the Top Layers & Bottom Layers. Your Layer Height, Top/Bottom Thickness value, and the total number of Top and Bottom Layers you enter all play a role in how it functions.
Most people recommend having between 4 and 8 top and bottom layers on your 3D prints. On reddit.com, a user claims the magic number for top layers to prevent sagging over the infill is 6 top layers and 2-4 bottom layers. The more important setting is the thickness of the layers because you can have 10 Top & Bottom Layers with a low layer height like 0.08mm, giving a 0.8mm thickness. This value would be very small for a 3D print with a solid top shell.
We recommend entering your Top/Bottom Thickness and letting Cura do the rest.
Top/Bottom Pattern
You have a few options for the Top/Bottom Pattern, including:
- Lines (Default)
- Concentric
- Zig Zag
The Lines pattern helps produce parts with an excellent surface finish, rigid lines in the directions in which they are extruded, and strong adhesion to model walls.
Concentric is ideal for creating watertight objects because it prevents the formation of air pockets and gaps. It will distribute strength equally in all directions. However, depending on your bed surface and the model’s design, this can change. Unfortunately, the surface quality isn’t known to be the best.
The Zig Zag pattern is similar to the Lines pattern, but instead of ending in the walls, the lines continue to extrude in the following line of skin. With this pattern, the surface quality is excellent, and the extrusion rate is more constant. The main drawback is that the Lines pattern adheres to the walls better.
Bottom Pattern Initial Layer
Another setting similar to the Top/Bottom Pattern is the Bottom Pattern Initial Layer. It is the infill pattern of just the bottom layer that is in contact with the build plate. The first layer’s pattern is significant because it directly influences factors like build plate adhesion and warping.
Lines are also the default Cura Bottom Initial Layer Pattern. The same options for the Top/Bottom Pattern setting: Concentric and Zig Zag patterns.
We’ll look at optimal Bottom Pattern Initial Layer patterns later.
Best Bottom Pattern Initial Layer in Cura
The Concentric pattern is the top Bottom Pattern Initial Layer in Cura. Due to less shrinking and the fact that it extrudes in all directions, this pattern is more resistant to warping and separation. Additionally, it adheres to the build plate more firmly. On 3D prints, it produces a lovely geometric pattern that looks wonderful.
This design is an excellent all-arounder and looks good. Because it adheres well to the walls, it can strengthen models and provide better bridges toward the print’s edges.
Depending on the model’s shape, the Concentric pattern isn’t always stable and can result in blobs in the middle of the print. This typically occurs on models with circular bottoms as opposed to square ones.
You might be able to resolve this by fine-tuning your extrusion. Another drawback is that because it conforms to the shape of your object, it occasionally doesn’t work well with the infill pattern you’re using. This is why it’s better suited to the bottom layer.
When using a raft, the lines pattern performs slightly better. For maximum strength, just make sure the print lines are parallel to the layer lines of the raft.
Best Top Layer Pattern for Cura
An excellent pattern for producing watertight prints and good overhangs is concentric. The Zig Zag pattern is the best top layer pattern in Cura if you want greater strength and a more continuous top surface, but it doesn’t adhere as well to the print’s walls. Also, it is equally powerful in all directions.
However, you can use the standard Lines pattern to strike a balance between strength and surface quality. It offers robust construction and good surface quality.
You can see a visual representation of all three patterns below.
Monotonic Top/Bottom Order
The Monotonic Top/Bottom Order setting ensures that your top and bottom lines are always extruded in the same direction, printing over each other. When you enable this option, the extruded lines are aligned so that the overlap between adjacent lines is consistent across the print’s surface. The way light reflects off the model makes the surfaces appear smoother and more uniform.
This results in a more appealing, even surface. Combining ironing and the monotonic setting can produce a more even surface.
In Cura, the Monotonic Top/Bottom Order setting is, by default, disabled. However, you should be aware that activating it might slightly lengthen printing time.
Check out this ModBot video that explains the distinction between prints that use Monotonic Ordering and those.
Enable Ironing in CURA
Ironing is another setting that can improve your top layers by passing the hot nozzle over the print’s surface to gently smooth the layers. During the pass, the nozzle maintains a low flow rate, which helps fill the gaps in the top layer.
In Cura, the Enable Ironing setting is, by default, disabled. Testing is advised to determine whether this setting makes a significant difference because using it may lengthen printing times and have undesirable effects on sloped surfaces.
Because ironing affects all top layers, you can save time by selecting Iron Only Highest Layers in Cura. You’ll need to use the search bar to look for the setting or click the three horizontal lines next to the search bar to set your settings visibility to “Expert.”
In Cura, you can find additional Ironing settings to enhance your top layer settings. One user suggests that a good starting point for your ironing flow should be 5% and that it should range from 4 to 10%. 10% is Cura’s default ironing flow.
To see Ironing in action and learn more helpful Ironing settings you can use in your prints, check out the video below.
How Do I Make My Top Layer 3D Print Better?
Some other settings that can improve your top surface aren’t in Cura’s Top/Bottom category.
Decreasing the Top/Bottom Line Width is another solution to improve the top and bottom layers. The default is in line with your regular Line Width, which is the same as your nozzle’s diameter. For a 0.4mm nozzle, you can try to decrease it by 10-15% and see what kind of difference it makes to your top and bottom layers.
Another option is to purchase a higher-quality nozzle, as some of the cheaper nozzles are of poor quality. A better nozzle should have smoother extrusion and more precise nozzle diameter.
Enhancing Combing can help a 3D print’s top and bottom layers. To lessen nozzle marks and blobs on the surfaces, you should change the setting to “Not in Skin,” which is the default.
Top Surface Skin Layers is a setting that controls how many additional skin layers are added to the top of your models. Though it isn’t frequently used in Cura, this enables you to apply particular settings only to those top surface layers. Even though some of these settings are hidden by Cura. You can get a more excellent top surface by lowering the Print Speed and the Jerk setting specifically for the Top Surface Skin. The top Surface Skin Layers’ default value is 0.
After clicking “Manage Setting Visibility…”, you’ll be taken to the main screen, where you can search for Cura settings. Find the setting and activate the view by searching for “top surface skin jerk.”
To see the setting, you must enable “Jerk Control” and apply a value of at least 1 for the Top Surface Skin Layers.
Let us know in the comments below or on our Facebook page to let us know your ideas, and we would appreciate seeing pictures of your works of art!
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